FIG. 1 shows a prior art Hall/Heroult cell for producing aluminum metal accumulating in molten pad 10 by electrolysis of alumina dissolved in a cryolite-based molten salt, bath 12, between a carbon cathode 14 and previously baked carbon anodes 16a, 16b. The carbon anodes are consumed with evolution of oxides of carbon, leaving butts such as in 16a.
The anodes include steel stubs 18 and copper or aluminum rods 20 clamped to a bridge 22 which can move up and down on a superstructure 23 to maintain or vary the distance between the bottom anode surfaces 24a, 24b and the molten metal pad 10.